Exported gas emits far more greenhouse gas emissions than coal, despite fossil-fuel industry claims it is a cleaner alternative, according to a major new research paper that challenges the controversial yet rapid expansion of gas exports from the US to Europe and Asia.
Coal is the dirtiest of fossil fuels when combusted for energy, with oil and gas producers for years promoting cleaner-burning gas as a “bridge” fuel and even a “climate solution” amid a glut of new liquefied natural gas (or LNG) terminals, primarily in the US.
But the research, which itself has become enmeshed in a political argument in the US, has concluded that LNG is 33% worse in terms of planet-heating emissions over a 20-year period compared with coal.
“The idea that coal is worse for the climate is mistaken – LNG has a larger greenhouse gas footprint than any other fuel,” said Robert Howarth, an environmental scientist at Cornell University and author of the new paper.
“To think we should be shipping around this gas as a climate solution is just plain wrong. It’s greenwashing from oil and gas companies that has severely underestimated the emissions from this type of energy.”
Drilling, moving, cooling and shipping gas from one country to another uses so much energy that the actual final burning of gas in people’s homes and businesses only accounts for about a third of the total emissions from this process, the research finds.
The large resulting emissions mean there is “no need for LNG as an interim energy source”, the paper says, adding that “ending the use of LNG should be a global priority”.
The peer-reviewed research, published on Thursday in the Energy Science & Engineering journal, challenges the rationale for a huge surge in LNG facilities along the US Gulf coast, in order to send gas in huge tankers to overseas markets. The US is the world’s leading LNG exporter, followed by Australia and Qatar.
Previous government and industry estimates have assumed that LNG is considerably lower emitting than coal, offering the promise that it could replace it in countries such as China, as well as aiding European allies menaced by the invasion of Ukraine by Russia, a major gas producer.
“US LNG exports can help accelerate environmental progress across the globe, enabling nations to transition to cleaner natural gas to reduce emissions and address the global risks of climate change,” Dustin Meyer, director of market development at the American Petroleum Institute, has said.
But scientists have determined that LNG expansion is not compatible with the world avoiding dangerous global heating, with researchers finding in recent years the leakage of methane, a primary component of gas and a potent planet-heating agent, from drilling operations is far higher than official estimates.
Howarth’s paper finds that as much as 3.5% of the gas delivered to customers leaks to the atmosphere unburned, much more than previously assumed. Methane is about 80 times more powerful as a greenhouse gas than carbon dioxide, even though it persists for less time in the atmosphere, and scientists have warned that rising global methane emissions risk blowing apart agreed-upon climate goals.
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Howarth’s research found that during LNG production, around half of the total emissions occur during the long journey taken by gas as it is pushed through pipelines to coastal terminals after it is initially drilled, usually via hydraulic fracturing, or fracking, from areas such as the US’s vast shale deposits.
The energy used to do this, along with the leaks, causes pollution that is exacerbated once the gas gets to the export facilities. There, it is supercooled to -162C (-260F) to become a liquid, which is loaded into huge storage containers on tankers. The tankers then travel long distances to deliver the product to client countries, where it is turned back into a gas and then burned.
“This whole process is much more energy intensive than coal,” said Howarth. “The science is pretty clear here: it’s wishful thinking that the gas miraculously moves overseas without any emissions..”
Howarth’s paper has caused something of a firestorm before its publication, with a draft of the study highlighted by climate campaigners such as Bill McKibben to the extent it was reportedly a factor in a decision earlier this year by the Biden administration to pause all new export permits for LNG projects.
This pause has enraged the oil and gas industry – prompting lawsuits – and its political allies. Last month, four congressional Republicans wrote to the US energy department demanding correspondence between it and Howarth over what they called his “flawed” and “erroneous” study.
Gas-friendly groups have also argued that the paper overstates emissions from LNG, an stance echoed by some energy experts. “It’s hard to swallow,” said David Dismukes, a leading Louisiana energy consultant and researcher. “Does gas have a climate impact? Absolutely. But is it worse than coal? Come on.”
Howarth said the result of this unusual scrutiny was “more peer review than I’ve ever had before”, with five rounds of review being conducted by eight other scientists. Howarth said: “I don’t consider the criticism valid at all – it feels like a political job.”
Howarth said the US has a “huge choice” to make in the presidential election, with Donald Trump vowing to undo Biden’s pause on his first day back in the White House to allow a raft of new LNG projects. Kamala Harris, meanwhile, has backed away from a previous plan to ban fracking but has promised action on the climate crisis.
More than 125 climate, environmental and health scientists wrote to the Biden administration last month to defend Howarth’s research and urge a continuation of the pause on LNG exports.
The Howarth paper’s findings are “plausible”, said Drew Shindell, a climate scientist at Duke University, who was not involved in the research.
“Bob’s study adds to a lot of literature now that shows the industry’s argument for gas is undermined by the option to go to renewables,” Shindell said. “The debate isn’t really about whether gas is slightly better or worse than coal, though. It should be about how both are terrible and that we need to get rid of both of them.”